UNITED NATIONS — The humanitarian crisis triggered by Boko Haram's “violent and inhuman campaign” is worsening, with 10.7 million people in need of aid in northeast Nigeria and parts of Cameroon, Chad and Niger, the U.N. humanitarian chief said Thursday.

Stephen O'Brien told the U.N. Security Council that although Boko Haram has lost much of the territory it once controlled as a result of military campaigns in the region, its raids and suicide bombings targeting civilians are still causing widespread death and destruction in those four countries.